1. Field of the Invention
This invention relates to a new and improved lubricant applying system and injector means, and is more particularly concerned with efficiently supplying lubricant at intermittent intervals to a plurality of points of use.
2. Description of Prior Art
Numerous and varied arrangements have been proposed for injecting lubricant to relatively movable surfaces, such as shaft bearings individually or collectively in multi-bearing arrangements. For the multi-bearing arrangements, centralized lubricating systems have been devised.
In an early example as shown in U.S. Pat. No. 2,141,022, a single-line lubricant supplying apparatus is disclosed in which a lubricant pump is controlled by a timing switch associated with a pressure switch responsive to pressure surge from a relief valve in a bypass located upstream from the lubricant injectors which have tell-tales functioning to close contacts in an electrical monitoring circuit which reveals whether or not all of the injectors are functioning properly. The injectors in that system have a lubricant charge displacing piston controlled by a pressure operated valve in the injector.
In a later U.S. Pat. No. 2,448,583 an injector structure is disclosed in which a metering piston has a tell-tale stem and is adapted for driving a metered charge of lubricant into a displacement chamber from which the lubricant is driven by a displacement piston into the lubricant line.
Attention is also directed to U.S. Pat. No. 3,995,717 which discloses a unilinear sequential firing piston arrangement in a lubricant injector, and in which the several injectors are shown as adapted to operate in parallel or in sequence.
However, there is still need for improvement in lubricant applying systems, having regard to simplification of structure combined with better operation, simpler replacement capability, reliable failure detection, and the like. As will become apparent, the ennumerated prior U.S. patents do not meet these desirable attributes which are supplied by the present invention.